Resend unconsumed scroll update from guest back to embedder (WebView Scroll Bubble).

chrome/test/data/extensions/platform_apps/web_view/scrollable_embedder_and_guest/guest.js

Index: chrome/test/data/extensions/platform_apps/web_view/scrollable_embedder_and_guest/guest.js
diff --git a/chrome/test/data/extensions/platform_apps/web_view/scrollable_embedder_and_guest/guest.js b/chrome/test/data/extensions/platform_apps/web_view/scrollable_embedder_and_guest/guest.js
new file mode 100644
index 0000000000000000000000000000000000000000..7a2d3f28e865d460b62a81c40ab2494218d41b7a
--- /dev/null
+++ b/chrome/test/data/extensions/platform_apps/web_view/scrollable_embedder_and_guest/guest.js
@@ -0,0 +1,25 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var LOG = function(msg) {
+  window.console.log(msg);
+};
+
+var embedder;
+
+function sendMessageToEmbedder(message) {
+  if (!embedder) {
+    LOG('no embedder channel to send postMessage');
+    return;
+  }
+  embedder.postMessage(JSON.stringify([message]), '*');
+}
+
+window.addEventListener('message', function(e) {
+  embedder = e.source;
+  var data = JSON.parse(e.data);
+  if (data[0] == 'connect') {
+    sendMessageToEmbedder('connected');
+  }
+});